git-annex/Types/UUID.hs
Joey Hess 65e903397c
implementation of peer-to-peer protocol
For use with tor hidden services, and perhaps other transports later.

Based on Utility.SimpleProtocol, it's a line-based protocol,
interspersed with transfers of bytestrings of a specified size.

Implementation of the local and remote sides of the protocol is done
using a free monad. This lets monadic code be included here, without
tying it to any particular way to get bytes peer-to-peer.

This adds a dependency on the haskell package "free", although that
was probably pulled in transitively from other dependencies already.

This commit was sponsored by Jeff Goeke-Smith on Patreon.
2016-11-17 18:30:50 -04:00

43 lines
892 B
Haskell

{- git-annex UUID type
-
- Copyright 2011 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE TypeSynonymInstances, FlexibleInstances #-}
module Types.UUID where
import qualified Data.Map as M
import qualified Data.UUID as U
import Data.Maybe
import qualified Utility.SimpleProtocol as Proto
-- A UUID is either an arbitrary opaque string, or UUID info may be missing.
data UUID = NoUUID | UUID String
deriving (Eq, Ord, Show, Read)
fromUUID :: UUID -> String
fromUUID (UUID u) = u
fromUUID NoUUID = ""
class ToUUID a where
toUUID :: a -> UUID
instance ToUUID UUID where
toUUID = id
instance ToUUID String where
toUUID [] = NoUUID
toUUID s = UUID s
isUUID :: String -> Bool
isUUID = isJust . U.fromString
type UUIDMap = M.Map UUID String
instance Proto.Serializable UUID where
serialize = fromUUID
deserialize = Just . toUUID